Method of making hollow glassware



[7J velata/.' zzz eid my 12 1927 R. w. cANFlELD METHOD OF MAKNG HOLLOWGLASSWARE med Maron 11, 192s 50h92? il? Patented July 12, 1927.

UNITED -STATES 1,635,764 PATENT OFFICE.

ROBERT W. CANFIELD, OF WEST HARTFORD, CONNECTICUT, ASSIGNOR TO HARTFORD-EMPIRE COMPANY, OF HARTFORD, CONNECTICUT, A CORPORATION OF DELAWARFMETHOD OF MAKING HOLLOW GLASSWARE.

Application llled'ltarh 11, 1925. Serial No. 14,674.

The present invention relates to the manufacture oLhollow glassware andit has particular relation to a method of making electric lamp bulbshaving substantially spherical body portions and substantiallycylindrical neck portions. 'i

Heretopfore, difficulty has been encountered in producing a bulb of thistypeby reason of the fact that the blank or parison, in

u stretching or elongating by its own weightA or by blowing, naturalformed itself into Y an elongated pear shape, having no welldencd neckportion, the lower or body portion merging gradually intov the upper ori neck portion. When the blow mold was closed about such a parison, theportion of the mold where the neck joins the body portion presented anabrupt shoulder which would contact with and compressthe parison andproduce .a permanent mark on the finished bulb at this point.

One of the objects of the present invention is to avoid the difficultyhereinabove mentioned by applying suction to the interior 2J of theparison after it has'been blown to the desired length and wall thicknessin order to remove a portion of the air within the parison, therebycontracting t-he neck of the parison sufficiently to be enclosed in ablow mold without contact therewith.

In the drawing:

Figure 1 is a view in side elevation and section illustrating theparison at the beginning of the necking-in operation;

37' Fig. 2 is a. similar view of the parison after the spinning ornecking-in operation;

Fig. 3 is a similar view of the parison at the conclusion of the saggingor elongating operation, the blow mold being shown in dotted lines;

Fig. 4 is a similar view of the parison illustrating its contracted neckportion after the application of suction thereto and showingthe.clearance between the parison and the blow mold; and

Fig. 5 is a similar view showing thebulb after being blown to final formin the blow mold. e

According to an ordinary method of producing electric lamp bulbs, acharge of glass1 obtained in any suitable manner` is first partiallyexpanded by a blow head or blow pipe l to form a. parison 2 of asubstantially ,A5 spherical shape l(Fig. l). The parison thus formed isthen rotated rbv the blow head and is allowed to sag and elongate,lwhichyoperation a nccking tool 3 is preferably applied to the parisonto` impart a preliminary configuration thereto.

As soon as the parison has sagged to substantially the shape shown inFig. 2, the rotary movement and mechanical necking-v in operations arediscontinued and the pari son is permitted to sag further and toclongate until the desired length and wall thickness are attained. Atthis stage (Fig. 3.) the parison is of the elongated pear shape abovereferred to, and comprises'a substantially hemispherical lower portion 4and a substantially cylindrical neck portion 5 of slightly lessdiameter. It will be understood that blowing pressure may be continuedthroughout the foregoing stages of forming i the parison.

At this stage the hemispherical lower portion 4 of the parison isapproxriiptely of the proper diameter to be enclosed in a new mold,without contact therewith, but the neck portion 5 exceeds the diameterof the corresponding portion 6 of the blow mold 7, as is indicated bydotted lines in Fig. 3. If the mold were to be closed around the parisonat this stage, the neck of the blow mold 7 would contact with the neck 5of the parison, producing a permanent mark thereon. In order, therefore,to reduce the diameter of this part 'of the parison suflciently to bealso enclosed in the blow mold without touching the walls thereof,suction is appliedvthrough the blowhead, which partially collapses andreduces the cross sectional area of the neck portion 5 of the parison,as indicated at 10 in Fig. 4.

The application of suction to the parison while reducing the diameter ofthe neck ortion 5 does not destroy or distort the bulbous shape of thelower portion 4, or contract the diameter ofthe extreme upper portion ofthe neck 5 to any great extent. This is by reason of the fact that thelower portion 4 is laterally braced by its hemisphercal bottom wall,which is Somewhat cooler and of greater rigidity'than the supcrjacentportions. ot' 'the parison, having been extruded from the mass of glassa greater period of time. and the upper or neck portion 5 iaterallybraced by the blowhead l.

".lhe blow mold 7 is then closed about the parison. as indicated iu andthe r0- tation olA the parison and the application of .turing finalform, without being marked or otherwise disgured as in the methodheretofore employed.

While in the foregoing description, the invention vis, described as inga plied in .the manufacture of electric lamp ulbs,.it will be understoodthat it is also applicable in the manufacture of hollow glass articlesof other, types.

I claim: .l Y

1. The method of making hollow glassware, which comprises blowin aparison and then impartinga contracte neck portion thereto' by removinga rtion of the air contained therein, enclosing said parison. inamold,and blowing it to final form therein.

'2. The .method of making hollow glassware, which comprises blowing aparison and then pneumatically necking-in a portion thereof by producingavdiflerential in the air "pressure within and without the parisonenclosin said parison in a mold, and blowing a 'to 86- nal form therein.A

3. The method of making hollow vglassware, which comprises blowing aparison, applying vsub-atmospheric pressure to the interior of saidparison to impart thereto la shape approximatin the contour of the blowmold employed,. enc osing the parison thus shaped in said blow mol andblowing the pa-rison ,to final form therein.

4. The method of making hollow glassware, which comprises blowing aparison and then applying suction to the interior of said parison-topartially contract a portion thereof and to form aj substantiallyspherical body portion and a substantially cylindrical neck portion,enclosing said pariorm son in a mold, and blowing it' to final therein.n l

5.' The method of making hollow glassware, which comprises blowing a;parison having the desired wall thickness, applying suction totheinterior of the parison to alter the shape thereof to conformsubstantially to the configuration of the blow mold, en-

closing same in'said mold and blowing the parison to final form therein.

6. The method of making an electric lamp bulb that comprises partiallyexpanding a initially s heroidal shape, rotatingv said parison anpermitting it to sag downward vto an elongated pear shape, with optionalfblow mol Signed at Hartford, Conn., this 10th day of March, 1925.

ROBERT VY. CANFIELD.A

`bod of molten glass to form a parison of

